Method for treating infectious diseases using a composition comprising plasma-derived immunoglobulin M (IgM)

ABSTRACT

Compositions and methods of the present invention prevent, inhibit or reduce the toxic effects of proteins and toxins secreted from microbes. A method for neutralizing microbial protein products in a subject comprises administering a composition to the subject, said composition comprising plasma-derived IgM and optionally one or more excipients in a pharmaceutical carrier, wherein the composition is administered in an amount effective to neutralize the microbial protein products.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/156,562, filed May 17, 2016, which claims priority to U.S.Provisional Patent Application No. 62/201,910, filed Aug. 6, 2015, thecontents of all of which are specifically incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to a method for treating infectiousdiseases comprising the administration to a patient in need thereof of acomposition containing plasma-derived IgM. The present invention alsorelates to a method for neutralizing secreted cytotoxic exotoxins duringactive microbial infections comprising the administration to a patientin need thereof of a composition containing plasma-derived IgM.

BACKGROUND OF THE INVENTION

Microbial species can become highly deleterious to an infected patient,if that individual cannot clear the infection, or if the patient isunresponsive to treatment. Infections can also become septic, spreadingfrom an infected organ into the blood stream. These septic infectionshave a poor outcome for patients, generally resulting in organ failureand death.

The problem is that most antibiotics target the live microbes themselvesto treat the infection. IgM has been characterized as preventing thetoxic septic aspects of bacterial infections due to systemic effects ofmicrobial endotoxins. These endotoxins are components of the cell wall(in-particular in Gram-negative bacteria). Neither of these methods oftreatment target or have been shown to target microbial exotoxins,superantigens, or secreted enzymes.

While it is well characterized that plasma-derived IgM can bind to andprevent endotoxin-mediated toxicity towards a patient, this does notaddress other proteins and toxins that are actively secreted frommicrobes. The toxic effects of endotoxins are typically a response tobacterial death or lysis induced by antibiotics or the immune system ofthe patient. These effects are separate from the toxic events that areobserved during a microbial infection due to proteins, such asexotoxins, that are actively secreted by the microbe. There remains aneed for compositions and methods that prevent, inhibit or reduce thetoxic effects of proteins and toxins secreted from microbes, other thanendotoxins.

SUMMARY OF THE INVENTION

The present invention is based on the findings of a surprisingneutralization effect of therapeutic doses of plasma-derived IgM toneutralize the deleterious impact of the secreted microbial proteins,such as secreted cytotoxic exotoxins, during active microbialinfections. The present invention makes use of the specificity ofplasma-derived IgM towards microbial proteins. As explained above, it iswell known that IgM binds microbial endotoxins, which are glycoproteins,and that this binding makes use of the general binding of IgM towardsglycoproteins and carbohydrates.

In the prior art, several monoclonal antibodies have been described, butare individually directed only to a single antigenic target. Naturalplasma-derived IgM, on the other hand, contains a plethora of potentialantigen binding sites that can target may different antigenssimultaneously and thus do not rely on a single treatment modality.

Furthermore, the present invention makes use of a source of IgM derivedfrom a waste stream of a standard blood fractionation process, forexample Grifols' Gamunex fractionation process.

Therefore, in a first aspect, the present invention refers to a methodfor treating infectious diseases comprising the administration to apatient in need thereof of a composition containing plasma-derived IgM.Stated another way, an embodiment of the present invention provides amethod for treating an infectious disease in a subject, said methodcomprising administering a composition to said subject, said compositioncomprising, consisting essentially of, or consisting of plasma-derivedIgM and optionally one or more excipients in a pharmaceutical carrier,wherein the composition is administered in an amount effective toneutralize microbial protein products in said patient.

In a second aspect, the present invention refers to a method forneutralizing secreted cytotoxic exotoxins during active microbialinfections comprising the administration to a patient in need thereof ofa composition containing plasma-derived IgM. Stated another way, anembodiment of the present invention provides a method for neutralizingmicrobial protein products in a subject, said method comprisingadministering a composition to said subject, said compositioncomprising, consisting essentially of, or consisting of plasma-derivedIgM and optionally one or more excipients in a pharmaceutical carrier,wherein the composition is administered in an amount effective toneutralize said microbial protein products.

Said cytotoxic exotoxins can be secreted by several microorganisms suchas Escherichia coli, Pseudomonas aeruginosa, Staphyloccuc aureus,Klebsiella pneumoniae, Streptococcus pneumoniae, Clostridium difficile,Clostridium botulinum, Aspergillus flavus and combinations thereof.

Preferably, the composition containing plasma-derived IgM is obtainedfrom a waste stream of a standard fractionation process. Theplasma-derived IgM has a purity of at least 70% (w/v), more preferablyat least 90% (w/v), and the most preferably at least 95% (w/v).

Also preferably, the dose of plasma-derived IgM to be administeredranges from 75 mg to 1 g per kilogram of the patient, preferably from 75mg/kg to 600 mg/kg, more preferably from 75 mg/kg to 300 mg/kg. The dosecan be administered on a daily, every other day, 3×/week or once perweek, regimen.

Optionally, the composition of plasma-derived IgM further comprisesother molecules selected from small molecule antibiotics, natural orsynthetic peptide antimicrobials, or proteins with antimicrobialproperties, or a combination thereof.

Examples of small molecule antibiotics are vancomycin and meropenem. Anexample of proteins with antimicrobial properties is lactoferrin.

In the method of the present invention, the composition ofplasma-derived IgM can be used alone or in combination with othertherapeutics molecules selected from the group consisting of therapeuticmolecules, including anti-inflammatory agents, and immunomodulators.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described below inreference to the following figures in which:

FIG. 1 shows the immunoreactivity of IgM against P. aeruginosa ExotoxinA. Absorbance OD readings at 450 nm are shown for a representativeELISA. The target antigen, P. aeruginosa Exotoxin A (P.A. ExA), wascoated on ELISA plates. Pooled plasma or IgM purified from the Gammunexprocess was used as sources of IgM. Various dilutions of this samplewere tested, as indicated, in PBS. Controls are wells that have not beencoated with antigen (Uncoated). Standard deviations are shown for eachbar.

FIGS. 2A and 2B show the neutralization of C. difficile Toxin Bcytotoxicity. Caco-2 cells (obtained from ATCC) were cultured in therecommended proliferation media. Cells were seeded in 96-well plates at8000 cells per well. 24 hours after initial plating, cells were treatedwith various IgM preparations and/or Clostridium difficile Toxin B asdescribed in the figure legend. Data for the relative number of cellsare shown as RLU, as measured by the Cell Titer Glow (Promega Corp.Madison, Wis., USA) assay performed according to the manufacturer'sinstructions. FIG. 2A demonstrates specificity of neutralization of C.difficile Toxin B (Tox B) by a two different batches of an IgG and IgMmixture (Frac. Conc. 45% and 70-80% IgM for solid black bars and hatchedbars, respectively, but not for the non-specific control, human serumalbumin (open bar); FIG. 2B further demonstrates neutralization of C.difficile Toxin B (ToxB) and rescue of viability of cells by increasingconcentrations of virtually pure IgM only (in micromole/L or uM; solidblack bar).

FIG. 3 shows the neutralization of C. difficile toxin-induced Caco-2permeability. Caco-2 cells were differentiated by typical methods inTranswell multiwell plate inserts. After 21 days of differentiation,Transepithelial electrical resistance (TEER) was measured immediatelybefore treatments initiated. Only those wells having a TEER measurementabove 200 were included in the experiment. After 16 hour treatments,TEER was measured to determine effects of treatments on TEER. Controls(non-treated cells) were set to 100% as the comparator. Treatment groupsare shown as relative percentages compared to the control group TEER.For Lucifer Yellow Permeability experiments, the cells with TEERs above200 and treated as described in the figure were incubated with LuciferYellow (Life Technologies, Grand Island, N.Y. USA) solution for 1 hourat 37° C. The Apical and Basal compartments of the Transwell insertswere sampled and assessed for the presence of Lucifer Yellow. Thepercentage of Lucifer Yellow which passed through the Caco-2 monolayerwas determined by fluorescence measurement of the samples. Dataforpercentage of Lucifer Yellow passing the Caco-2 monolayer arepresented as fold increase in permeability relative to Controls whichwere set to a value of 1. A dose-response is demonstrated to C.difficile toxin B (Tox B)-mediated cell permeability to the dye, LuciferYellow (A) or to electrical resistance of the epithelial layers (TEER,vide supra) (B); in both cases, a non-toxin B control is included (lefton graph). The positive neutralizing effect of co-administration of IgMwith Toxin B (Tox B) is demonstrated in the Lucifer Yellow permeabilitystudy. For the representative permeability in (C), a control sample (noprotein, far left bar) shows the permeability of Lucifer Yellow alone,while the remaining bars show the increased permeability by C. difficileToxin B (Tox B), without or without added human serum albumin (HSA), buta neutralizing effect of Toxin B (Tox B) in the presence of IgM (FracC), second bar from right). For the representative transepithelialelectrical resistance measurements (TEER) in (D), a control samplewithout protein (solid bar, far left) demonstrates the normal electricalresistance of the cell layer, which is considerably reduced in thepresence of C. difficile Toxin B (Tox B) both without (solid bar, secondfrom left), and with human serum albumin (HSA; solid bar, far right).Restoration of TEER by IgM (Frac. C) in the presence of Toxin B (ToxB)is shown in this figure (Tox B+Frac C; second from right).

FIGS. 4A and 4B show the neutralization of Pseudomonas aeruginosaExotoxin A cytotoxicity. Caco-2 cells (obtained from ATCC) were culturedin the recommended proliferation media. Cells were seeded in 96-wellplates at 4000 cells per well. 24 hours after initial plating, cellswere treated with various IgM preparations and/or Pseudomonas aeruginosaExotoxin A as described in the figure legend. Data for the relativenumber of cells are shown as RLU, as measured by the Cell Titer Glow(Promega Corp. Madison, Wis., USA) assay according to the manufacturer'sinstructions. FIG. 4A demonstrates specificity of neutralization ofPseudomonas Exotoxin A (ExA) by a two different batches of an IgG andIgM mixture (Frac Conc. 45% and 70-80% IgM for solid black bars andhatched bars, respectively, but not for the non-specific control, humanserum albumin (open bar); FIG. 4B further demonstrates neutralization ofPseudomonas Exotoxin A (P.A. ExA) and rescue of viability of cells byincreasing concentrations of virtually pure IgM only (in micromole/L oruM; solid black bars).

FIG. 5 shows the neutralization of Clostridium tetani toxoid effects.Human peripheral blood mononuclear cells were cultured in RPMI with 10%heat inactivated human serum. For proliferation assays, 3×105 cells wereseeded in each well of a 96 well plate using culture media. Cells weretreated as described in the figure legend. Relative cell proliferationwas determined by Cell Titer Glow (Promega Corp. Madison, Wis., USA) andperformed according to manufacturer's instructions. Cell proliferationwas standardized against experimental controls to a value of 1.

FIG. 6 shows the immunoreactivity of IgM against Pseudomonas aeruginosa,Streptococcus pneumoniae, and Klebsiella pneumoniae bacteria. AbsorbanceOD readings at 450 nm are shown for representative whole cell ELISAs.Target antigens were formaldehyde treated Pseudomonas aeruginosa (whitebars), Streptococcus pneumoniae (diagonal striped bars), and Klebsiellapneumoniae (black bars), whole bacteria cells were coated on ELISAplates. Controls bacteria coated wells incubated with secondary antibodyonly or wells that have not been coated with antigen.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention provides a method for treating aninfectious disease in a subject, said method comprising administering acomposition to said subject, said composition comprising, consistingessentially of, or consisting of plasma-derived IgM and optionally oneor more excipients in a pharmaceutical carrier, wherein the compositionis administered in an amount effective to neutralize microbial proteinproducts in said patient.

Another embodiment of the present invention provides a method forneutralizing microbial protein products in a subject, said methodcomprising administering a composition to said subject, said compositioncomprising, consisting essentially of, or consisting of plasma-derivedIgM and optionally one or more excipients in a pharmaceutical carrier,wherein the composition is administered in an amount effective toneutralize said microbial protein products.

Another embodiment of the present invention provides a compositioncomprising, consisting essentially of, or consisting of plasma-derivedIgM and optionally one or more excipients in a pharmaceutical carrier.According to particular embodiments, the one or more excipients and/orthe pharmaceutical carrier are synthetic, i.e., non-naturally occurring.

As used herein, “neutralizing” microbial protein products refers toreducing, preventing or eliminating the toxic effects of microbialprotein products on the subject, e.g., reducing, preventing oreliminating exotoxin-mediated toxicity towards a patient.

According to particular embodiments, the microbial protein products areselected from the group consisting of exotoxins, superantigens andsecreted enzymes. Preferably, the microbial protein products do notinclude microbial endotoxins.

According to particular embodiments, the subject has been diagnosed witha bacterial infection prior to administration of the composition.

As used herein, the term “pharmaceutically acceptable carrier” refers toa diluent, adjuvant, excipient, or vehicle with which plasma-derived IgMof the present invention is administered. Such carriers can be sterileliquids, such as water and oils, including those of petroleum, animal,vegetable or synthetic origin, such as peanut oil, soybean oil, mineraloil, sesame oil and the like, polyethylene glycols, glycerin, propyleneglycol or other synthetic solvents. Saline solutions and aqueousdextrose and glycerol solutions can also be employed as liquid carriers,particularly for injectable solutions. According to particularembodiments, the pharmaceutically acceptable carrier is synthetic (i.e.,the carrier is not naturally-occurring).

Non-limiting examples of suitable excipients include starch, glucose,lactose, sucrose, gelatin, silica gel, sodium stearate, glycerolmonostearate, talc, sodium chloride, glycerol, propylene glycol, water,ethanol and the like. Excipients may also include wetting or emulsifyingagents, or pH buffering agents such as acetates, citrates or phosphates;antibacterial agents such as benzyl alcohol or methyl parabens;antioxidants such as ascorbic acid or sodium bisulfite; chelating agentssuch as ethylenediaminetetraacetic acid; and agents for the adjustmentof tonicity such as sodium chloride or dextrose. According to particularembodiments, the one or more excipients are synthetic (i.e., theexcipients are not naturally-occurring).

The cytotoxic exotoxins can be secreted by several microorganisms suchas Escherichia coli, Pseudomonas aeruginosa, Staphyloccuc aureus,Klebsiella pneumoniae, Streptococcus pneumoniae, Clostridium difficile,Clostridium botulinum, Aspergillus flavus and combinations thereof.

Preferably, the composition containing plasma-derived IgM is obtainedfrom a waste stream of a standard fractionation process. Theplasma-derived IgM has a purity of at least 70% (w/v), more preferablyat least 90% (w/v), and the most preferably at least 95% (w/v).

Also preferably, the dose of plasma-derived IgM to be administeredranges from 75 mg to 1 g per kilogram of the patient, preferably from 75mg/kg to 600 mg/kg, more preferably from 75 mg/kg to 300 mg/kg. The dosecan be administered on a daily, every other day, 3×/week or once perweek, regimen.

Optionally, the composition of plasma-derived IgM further comprisesother molecules such as small molecule antibiotics, natural or syntheticpeptide antimicrobials, or proteins with antimicrobial properties, or acombination thereof.

Examples of small molecule antibiotics are vancomycin and meropenem. Anexample of proteins with antimicrobial properties is lactoferrin.

In the method of the present invention, the composition ofplasma-derived IgM can be used alone or in combination with othertherapeutics molecules selected from the group consisting of therapeuticmolecules, including anti-inflammatory agents, and immunomodulators.

The embodiments described herein are intended to be exemplary of theinvention and not limitations thereof. One skilled in the art willappreciate that modifications to the embodiments and examples of thepresent disclosure may be made without departing from the scope of thepresent disclosure.

The embodiments of the invention are described above using the term“comprising” and variations thereof. However, it is the intent of theinventors that the term “comprising” may be substituted in any of theembodiments described herein with “consisting of” and “consistingessentially of” without departing from the scope of the invention.Unless specified otherwise, all values provided herein include up to andincluding the starting points and end points given.

The following examples further illustrate embodiments of the inventionand are to be construed as illustrative and not in limitation thereof.

EXAMPLES Example 1. Immunoreactivity of IgM with Exotoxins, SecretedBacterial Enzymes and Superantigens

Several ELISAs were developed by the present inventors to assessimmunoreactivity towards a variety target antigens produced by thebacteria P. aeruginosa, Staphilococcus aureus, C. tetani, and C.difficile (see Table 1). Surprisingly, all proteinacious exotoxins andenzymes were recognized by plasma-derived IgM. A positive reactivity forall protein-based antigens assessed from these pathogens was observed.An example ELISA showing reactivity of IgM in a purified preparation andin plasma is shown in FIG. 1.

TABLE 1 Summary of antigenic targets that have been assessed by ELISA.The symbol “+” indicates positive reactivity. E. coli LPS was used as apositive control, as it is well characterized that IgM has reactivityagainst Gram-negative endotoxins. Species/Antigen IgM Reactivity P.aeruginosa Exotoxin A + S. aureus TSST-1 + S. aureus Staphylokinase + C.difficile Toxoid A + C. difficile Toxoid B + C. difficile Toxin A + C.difficile Toxin B + C. tetani Tetanus Toxoid + E. coli 0111:B4 LPS +

Example 2. Neutralization of Cytotoxic Effects of C. difficile Toxin B

A preliminary goal of the present invention was to provideproof-of-concept for IgM neutralizing exotoxins. Since C. difficile isan intestinal infection, it was chosen to utilize a physiologicallyrelevant cell line for studies. Caco-2 cells are an epithelialcolorectal cell line routinely used for intestinal permeability studies.Caco-2 to be used in cytotoxicity assays was developed. Incubation timeand C. difficile Toxin B concentrations were optimized (data not shown).Incubation of Toxin B for 24 hours did not show any toxicity and asincubation time increased the cytotoxicity also increased. Additionally,we determined that 25 ng/mL gave the highest assay window of toxicity at48 hours and showed a plateau at this point. Concluding assay conditionswere set at 15 ng/mL Toxin B with 48 hours incubation with proliferatingcells. Using these conditions neutralization of toxin with purificationfractions enriched for IgM was assessed and compared, as well aspurified IgM (FIG. 2). Fraction A contains 40-50% IgM and Fraction Bcontains 70-80% IgM. HSA had no effect on Toxin B toxicity, whereas 2different fractions containing IgM neutralized the toxin (FIG. 2A).Purified IgM (≥95% IgM) was also shown to be efficacious in neutralizingC. difficile Toxin B (FIG. 2B). There are clearly neutralizingantibodies toward C. difficile in Fraction A, Fraction B, and purifiedIgM.

Example 3. Neutralization of C. difficile Toxin B-Induced Permeability

As mentioned in the previous example Caco-2 cells are a wellcharacterized model of intestinal epithelia transport and permeability.One of the known consequences of C. difficile toxins are intestinalpermeability. To test whether purification fractions containing IgMcould neutralize this toxin effect, Caco-2 for use as an intestinalpermeability model was developed. In this model, Caco-2 cells aredifferentiated in a monolayer on a well insert with a permeable membranefor 21 days. Following differentiation, permeability can be monitored bymeasuring the ability of fluorescent small molecules (Lucifer Yellow inthis case) to pass through the cell monolayer and by using the TEERmethod (TransEpithelial Electrical Resistance) to measure the electricalresistance imparted by the monolayer. When the cells have increasedpermeability, the amount of Lucifer Yellow found on the basolateral sideof the membrane is also increased. In terms of electrical resistance,cells with higher permeability have lower resistance. To show that thesedifferences can be measured, a dose response of C. difficile Toxin B(FIGS. 3A and 3B) was performed. Both the ability of Lucifer Yellow toacross the monolayer and the electrical resistance of the monolayer hadappropriate corresponding changes in response to increasing doses ofToxin B. The ability of Fraction C (enriched to 90-95% IgM) toneutralize the Toxin B—mediated permeability was tested. Fraction C andToxin B were pre-incubated for 1 hr to allow IgM to bind to toxin.Following pre-incubation, cells were treated with the Fraction C andToxin B mixture for 16 hours. After this 16 hour period cells wereassessed for permeability by Lucifer Yellow diffusion across themonolayer (FIG. 3C) and for monolayer TEER (FIG. 3D). For both assaymethods, Fraction C provided protection against the Toxin B, whereas HSAhad no effect on Toxin B. Lucifer Yellow had a complete reversal whileresistance showed only a partial rescue. This is perhaps due to TEERbeing more sensitive than Lucifer Yellow assay method.

Example 4. Neutralization of Cytotoxic Effects of Pseudomonas aeruginosaExotoxin a

Given the positive data from Caco-2 cells with neutralization of C.difficile Toxin B, a similar assay in Caco-2 was developed to testPseudomonas aeruginosa Exotoxin A. When Fraction A or Fraction B wereassessed in this model, neutralization of Exotoxin A was observed (FIG.4A). Interestingly, the opposite results were found with Exotoxin A withrespect to the efficaciousness of the fractions, compared to C.difficile Toxin B; the Fraction A was more potent than Fraction B forneutralization of Exotoxin A. Additionally, we also observedneutralization of Pseudomonas aeruginosa Exotoxin A cytotoxicity usingpurified IgM (FIG. 4B).

Example 5. Neutralization of Clostridium tetani Toxoid

Tetanus toxin is a highly potent neurotoxin that blocks the release ofGABA. Most individuals in the United States are vaccinated for tetanus.As a model of tetanus toxin neutralization, a non-toxic toxoid form oftetanus toxin was utilized to assess whether purified IgM can neutralizethis protein. It was shown antigenic binding of IgM to the tetanustoxoid (see Table 1). As the toxoid shows no GABA release blockage,IgM's neutralization effect was assessed by proliferation of peripheralblood mononuclear cells (PBMCs). It is known that stimulation of TCRantigens can induce proliferation of T-cells and tetanus is a describedstimulant for this proliferation. Therefore, tetanus toxoid induced PBMCproliferation was tested, in the presence and absence of IgM (FIG. 5). A3-fold increase in cell number in the presence of tetanus toxoid alonewas observed, whereas co-treatment with IgM almost completely blockedthis effect at 2.5 μM and showed complete inhibition at 5 μM.

Example 6. IgM has Antigenic Recognition of Diverse Microbes

To better understand the diversity of various targets a variety ofELISAs were performed. A variety of commercially available ELISA kitswere used detecting reactivity with both bacterial and viral pathogens.Additionally, an ELISA-based assays was utilized in which whole heatkilled or formaldehyde treated microbes were coated on ELISA plates.This assessment allows assessment of reactivity against “global” antigentargets produced by microbes. Data for all ELISAs and Whole Cell ELISAsare summarized in Table 2 and from these data it can be concluded thatIgM has ubiquitous antigenic recognition. An example ELISA data set forIgM reactivity in whole cell ELISAs using Pseudomonas aeruginosa,Streptococcus pneumoniae, and Klebsiella pneumoniae bacteria are shownin FIG. 6.

TABLE 2 Summary of antigenic targets that have been assessed by ELISAand Whole Cell ELISA. The symbol “+” indicates positive IgM reactivityand “+ weak” indicates weak IgM reactivity based on the kit standardcontrols. IgM Species Reactivity Viral ELISAs Adenovirus + weakCytomegalovirus + weak Measles + weak Mumps + Rubella + RespiratorySyncytial Virus + Varicella-Zoster + Rotavirus + Bacterial Whole E. coli0111:B4 + Cell ELISAs Helicobacter pylori + Listeria monocytogenes +Legionella pneumophila + Lactobacillus rhamnosus + Pseudomonasaeruginosa + Porphyromonas gingivalis + Staphylococcus aureus +Staphylococcus aureus (Prot. A def.) + Streptococcus pneumoniae +Clostridium difficile + Klebsiella pneumoniae ATCC 10031 + Klebsiellapneumoniae UNT-127-1 + Pseudomonas aeruginosa UNT-152-1 + Streptococcuspneumoniae UNT-011-1 + Fungal Whole Candida albicans + Cell ELISAs

What is claimed is:
 1. A method for treating a microbial infection, themethod comprising administering to a subject in need thereof atherapeutically effective amount of a composition consisting essentiallyof a plasma-derived IgM, and, optionally one or more excipients in adiluent or vehicle, wherein: the plasma-derived IgM is obtained from awaste stream of a standard blood fractionation process; and themicrobial infection is an infection with a microorganism selected fromthe group consisting of Aspergillus flavus, Candida albicans,Streptococcus pneumonia, Clostridium difficile, Clostridium tetani,Listeria monocytogenes, Lactobacillus rhamnosus, Escherichia coli,Pseudomonas aeruginosa, Klebsiella pneumoniae, Helicobacter pylori,Legionella pneumophila, and Porphyromonas gingivalis, and wherein themicrobial infection is not an infection with Staphylococcus aureus. 2.The method of claim 1, wherein the microbial infection is not aninfection with Clostridium botulinum.
 3. The method of claim 1, whereinthe plasma-derived IgM is administered to a subject in a dose of 75 mgto 1 g per kilogram of the subject.
 4. The method of claim 1, whereinthe plasma-derived IgM is administered to a subject in a dose of 75 mgto 600 mg per kilogram of the subject.
 5. The method of claim 1, whereinthe plasma-derived IgM is administered to the subject in a dose of 75 mgto 300 mg per kilogram of the subject.
 6. The method of claim 1, whereinthe plasma-derived IgM is administered daily, every other day, 3 timesper week, or once per week.
 7. A method for treating a microbialinfection, the method comprising administering to a subject in needthereof a therapeutically effective amount of a composition consistingessentially of: a therapeutic molecule consisting essentially ofplasma-derived IgM, and, optionally one or more excipients in a diluentor vehicle, wherein the microbial infection is an infection with amicroorganism selected from the group consisting of Aspergillus flavus,Candida albicans, Streptococcus pneumoniae, Clostridium difficile,Clostridium botulinum, Clostridium tetani, Listeria monocytogenes, andLactobacillus rhamnosus; and wherein the microbial infection is not aninfection with Staphylococcus aureus.
 8. The method of claim 7, wherein:the microbial infection is a fungal infection; and the fungal infectionis an infection with a fungus selected from the group consisting ofAspergillus flavus and Candida albicans.
 9. The method of claim 7,wherein: the microbial infection is a bacterial infection; and thebacterial infection is an infection with bacteria selected from thegroup consisting of Streptococcus pneumoniae, Clostridium difficile,Clostridium botulinum, Clostridium tetani, Listeria monocytogenes, andLactobacillus rhamnosus.
 10. The method of claim 7, wherein: theplasma-derived IgM is obtained from a waste stream of a standard bloodfractionation process; the microbial infection is a bacterial infection;the bacterial infection is an infection with bacteria selected from thegroup consisting of Streptococcus pneumoniae, Clostridium difficile,Clostridium tetani, Listeria monocytogenes, and Lactobacillus rhamnosus;and the bacterial infection is not an infection with Staphylococcusaureus.
 11. The method of claim 7, wherein: the plasma-derived IgM isobtained from a waste stream of a standard blood fractionation process;the microbial infection is a bacterial infection; the bacterialinfection is an infection with bacteria selected from the groupconsisting of Streptococcus pneumoniae, Clostridium difficile,Clostridium botulinum, Clostridium tetani, Listeria monocytogenes, andLactobacillus rhamnosus; and the plasma-derived IgM is administered at adosage sufficient to neutralize cytotoxic exotoxins secreted by thebacteria in the subject.
 12. The method of claim 8, wherein the fungusis Aspergillus flavus.
 13. The method of claim 8, wherein the fungus isCandida albicans.